libata: struct device - replace bus_id with dev_name(), dev_set_name()

Cc: Jeff Garzik <jgarzik@redhat.com>
Cc: Tejun Heo <tj@kernel.org>
Signed-off-by: Kay Sievers <kay.sievers@vrfy.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>